(1) Field of Invention
The present invention relates to a method for providing a roller assembly for creating decorative patterns on a wood material surface, and for using the roller assembly to create decorative patterns on wood material surfaces.
(2) Prior Art
Wood material surfaces, such as those processed to panels, are usually surface coated. Apart from desirable properties, such as the resistance against wear and tear, and the protection against moisture, achieving a certain attractive outward appearance is also desired. Typical wood materials are chip board, high- and medium-density fiberboard, plywood and OSB board, however, in the context of the present invention, also solid wood and solid wood boards are counted amongst the wood materials.
Coating methods known from the prior art include not only methods wherein synthetic resins are pressed together with the wood material, but also those wherein at least one, usually, however, a plurality of paint or lacquer coats are applied in liquid form, which are subsequently dried or hardened. Such a coating method is relatively cheap and simple. To apply the individual coats, preferably rollers are used, which roll on the wood material surface and thereby transfer the previously received liquid paint or lacquer (indirect gravure printing).
A typical structure of such a coating comprises first a primer, followed by a decorative paint coat, on which, in turn, one or more finishing lacquer coats are applied. The lacquer coats complete the surface coating. While the colored appearance is provided by the decorative coat and sometimes also by the primer, the surface properties, such as roughness and reflective behavior, are determined by the finishing lacquer coats. Different lacquer coats can also have different opacities.
Sometimes it may be desirable to structure the surface in a three-dimensional manner, either by means of an optical effect, or by forming the surface in a three-dimensional manner. When liquid paint or lacquer coats are applied without a subsequent pressing process, real three-dimensional forming of the surface is difficult, but it is possible to provide optical structuring, by applying, for example, lacquer coats having different properties in different areas, in particular having a different degree of gloss. It is thus possible to provide a surface having no unevenness with a three-dimensional appearance.
In particular with imitation wood, it is often desirable not only to imitate the pore structure of the wood to be imitated by means of colored paint, but to give it a more realistic appearance by using, for example, matt lacquer to highlight the pores and glossy lacquer for the areas surrounding them, to give an approximately three-dimensional impression. For this purpose it is necessary, however, to apply each of the two types of lacquer with its own roller. At least one of these rollers must have a surface structure, so that it applies lacquer to the wood material surface only with portions of its surface. A roller with a surface, which applies lacquer only in portions, for example, for creating optical pores, will be referred to as a structured lacquer application roller in the following.
For a realistic, consistent optical appearance, the pore pattern which is evoked by the top lacquer coats must be matched with the underlying decorative paint coat. To achieve this it is necessary according to the prior art to provide a structured lacquer application roller for each of the roller or rollers used for a decorative paint coat, referred to as decorative paint rollers in the following, whereby the lacquer application roller has to be matched to the decorative paint pattern produced by the decorative paint rollers in such a way, that together they create a decorative pattern having a three-dimensional effect. This causes the problem that the design, and in particular the precise production of a structured plate involves time and cost with each new decorative pattern. Providing such roller assemblies of decorative paint rollers and structured lacquer application rollers for each decorative pattern separately is very cumbersome.